Historically meter readings of the consumption of utility resources such as water, gas, or electricity have been accomplished manually by human meter readers at customers premises. The relatively recent advances in this area include collection of data by telephone lines, radio transmission, walk-by, or drive-by reading systems using radio communications between the meters and meter reading devices. Although some of these methods require close physical proximity to the meters, they have become more desirable than the manual reading and recording of the consumption levels. Over the last few years, there has been a concerted effort to automate meter reading by installing fixed networks that allow data to flow from the meter to a host computer system without human intervention. These systems are referred to in the art as Automated Meter Reading (AMR) systems.
A mobile AMR system comprises an Encoder-Receiver-Transmitter (ERT), which is a meter interface device attached to the meter and either periodically or in response to a request transmits utility consumption data. Today, some ERTs transmit AM, while others transmit FM signals. In other fields, there are systems configured to receive both types of signals concurrently. For example in the automotive field, radio receivers possessing both AM and FM reception are common.
The Kaufman (U.S. Pat. No. 4,001,702), Funabashi (U.S. Pat. No. 4,070,628), von der Neyen (U.S. Pat. No. 4,304,004), Mason (U.S. Pat. No. 3,206,680), Peil (U.S. Pat. No. 3,665,507), Lundquist et al (U.S. Pat. No. 3,745,467), Ohsawa et al. (U.S. Pat. No. 3,919,645) and Denenberg (U.S. Pat. No. 3,971,988) patents are all radio receivers capable of receiving AM and FM signals; however, most automotive radio receivers, such as the ones of Funabashi, Mason, Peil, Lundquist et al, Ohsawa et al, and Denenberg receive AM and FM signals as alternatives and merely allow the user to select between the two signals. As such, two kinds of traditional receivers are required for demodulation and decoding of the two possible transmission types, which complicates the required hardware, entails extra cost, etc.